The European Commission wants to further reduce air pollution in Europe. Although the situation has improved substantially over the last few decades, there are still significant areas of concern with regard to certain pollutants that are particularly harmful to human health (respiratory diseases) and damaging to the environment (acidification, eutrophication, etc.). The anti-pollution programme that the Commission has launched to that effect is called the “Clean Air for Europe” or CAFE programme.

Air pollution has been one of Europe’s main concerns since the late 1970s. Over the last few decades, the rapid growth in industry and increased reliance on cars and public transport has contributed to a rapid decline in air quality, from smog and acid rain to asthma and other respiratory diseases.

Distribution of stations by thresholds of 99.73 percentile of the hourly SO2 concentrations for the year 2011. The chart is based on the 99.73 percentile of the SO2 hourly concentrations, corresponding to the 25th highest SO2 concentration when data availability is 100% over the year.

In the air quality directive (2008/EC/50), the EU has set two limit values for sulphur dioxide (SO2) for the protection of vegetation within the zones designated by member states: the SO2 annual mean value may not exceed 20 micrograms per cubic metre (µg/m3) and the SO2 mean value for the winter period (1 October to 31 March) may not exceed 20 micrograms per cubic metre (µg/m3).

In the air quality directive (2008/EC/50), the EU has set a limit value for carbon monoxide (CO) for the protection of human health: the CO maximum daily 8-hour mean values may not exceed 10 milligrams per cubic metre (mg/m3).

In the air quality directive (2008/EC/50) the EU has set two limit values for sulphur dioxide (SO2) for the protection of human health: the SO2 hourly mean value may not exceed 350 micrograms per cubic metre (µg/m3) more than 24 times in a year and the SO2 daily mean value may not exceed 125 micrograms per cubic metre (µg/m3) more than 3 times in a year.

In the air quality directive (2008/EC/50), the EU has set a target value and a long term objective value for ozone (O3) for the protection of human health. Target value: the maximum daily eight-hour mean may not exceed 120 micrograms per cubic metre (µg/m3) on more than 25 days per calendar year averaged over three years. Long term objective value: the maximum daily eight-hour mean may not exceed 120 micrograms per cubic metre (µg/m3) within a calendar year.

In the directive 2004/107/EC (Fourth Daughter Directive), the EU has set a target value for polycyclic aromatic hydrocarbons (PAH) for the protection of human health; the target is defined in terms of concentration of benzo(a)pyrene (BaP) which is used as a marker substance for PAHs generally: the BaP annual mean value may not exceed 1 nanogram per cubic metre (ng/m3). The target value enters into force 31.12.2012.

The red line corresponds to the EU limit value of 125 μg/m3, EU Member States only.
The graph is based on the 99.18 percentiles of the daily mean concentration values for each Member State; the boxes
present the range of the 99.18 percentiles at all stations types (in μg/m3) with data officially reported by the EU Member
States and how they relate to the daily limit value set by EU legislation (marked by the red line).
The diagram indicates the lowest and highest observations, the means and the lower and upper quartiles. The lower quartile
splits the lowest 25 % of the data and the upper quartile splits the highest 25 % of the data.

Due to lack of detailed land cover data and/or rural ozone data Iceland and Norway are not included until 2006 and onwards. Switzerland have not been included in the analysis for the entire period 1996-2007 due to the same reasons. Turkey is not included in the analysis 1996-2008.